Automotive Air Conditioning Information Forum (Archives)

CorvairGeek on Sat May 23, 2015 11:41 PM

Year: '84 ish
Make:
Refrigerant Type: R12
Country of Origin: United States

This is probably a pretty 'nerdy' question about ancient history, but I'm sure GM Tech will know, and maybe others.
What was the significance of the change from 'heavy' to 'light vee belt clutches in the '84-'85 time frame? It anecdotally seems like it was phased in on the smallest/roughest engines before the V8s. Maybe it was all about the short vs long shaft R4s (as I understand, never measured them myself) and the pulley diameter difference. Just curious...

Thanks,

Jerry


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Jerry

Edited: Sat May 23, 2015 at 11:54 PM by CorvairGeek

GM Tech on Sun May 24, 2015 2:51 PM

Probably the change from 4 pole to 6 pole coils- the 6 poles were considered the lightweight clutch design- which the R-4 changed to, to commonized the V-5, H-6 and R-4 to use the same clutches and did away with the old R-4 "bolted on" pulley design in late 80's. Lighter weight was always better in engine components for mpg. The compressor Front heads had to be redesigned as well. The 6-pole design also allowed for serpentine belt use as well- could not do that with the old R-4 vee belt, bolt on, 4-pole coil and pulley. It hapened at same time trucks went to serpentine belts- so this was probably the driving force to change the design. If the R-4 was to continue- it had to have a serpentine pulley design.

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

CorvairGeek on Mon May 25, 2015 10:19 PM

I do believe that explains it, thanks! I just couldn't put it together on my own.

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Jerry